APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

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APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by APOD Robot » Fri Dec 04, 2015 5:08 am

Image Cygnus: Bubble and Crescent

Explanation: These clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. Caught within the telescopic field of view are the Soap Bubble (lower left) and the Crescent Nebula (upper right). Both were formed at a final phase in the life of a star. Also known as NGC 6888, the Crescent was shaped as its bright, central massive Wolf-Rayet star, WR 136, shed its outer envelope in a strong stellar wind. Burning through fuel at a prodigious rate, WR 136 is near the end of a short life that should finish in a spectacular supernova explosion. recently discovered Soap Bubble Nebula is likely a planetary nebula, the final shroud of a lower mass, long-lived, sun-like star destined to become a slowly cooling white dwarf. While both are some 5,000 light-years or so distant, the larger Crescent Nebula is around 25 light-years across.

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by Ann » Fri Dec 04, 2015 5:21 am

Hooray! Ivan Eder got an APOD, and that is so well-deserved! :D
APOD Robot wrote about the Soap Bubble and the Crescent Nebula:
Both were formed at a final phase in the life of a star.
Maybe so, but there is a very big difference between the stars that created the two nebulas. WR 136, the star responsible for blowing the Crescent Nebula, is still very much a functioning star that shines by fusing lighter elements into heavier ones. The star that blew the Soap Bubble nebula is long dead, a stellar cinder slowly radiating its remnant heat into space.

The Crescent Nebula is bright and turbulent, a testament to the power and unpredictability of Wolf-Rayet stars. The faint, perfect sphere of the Soap Bubble nebula speaks of a "Juliet's death among flowers in the river" kind of demise for the star that created this delicate stellar death shroud.

Starsurfer must love this APOD!

Ann
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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by Boomer12k » Fri Dec 04, 2015 9:27 am

Dearly Beloved....please bow your heads in remembrance of the Soap Bubble Nebula....a moment of silent reflection....

What a cool image!!

2001: Space Odyssey "STAR CHILD" meets...or VS....THE BRAIN FROM BEYOND TIME!!!!!! Super low budget 1950's Sci-fi movie starring John Agar, (no doubt).... :lol2:

Really nice job.

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by heehaw » Fri Dec 04, 2015 10:19 am

There's something ... I don't know ... you might almost say "otherworldly" about this image....

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by gregeli » Fri Dec 04, 2015 4:02 pm

What is the name of the telescope that captured this image?

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by neufer » Fri Dec 04, 2015 4:48 pm

Ann wrote:
The star that blew the Soap Bubble nebula is long dead, a stellar cinder slowly radiating its remnant heat into space.
  • A very hot cinder (illuminating the Soap Bubble) from a recently deceased hydrogen burning star.

    The star that blew off the Soap Bubble nebula a mere few thousand years ago
    currently illuminates the same as it transforms into a long lived white dwarf star.
Joe Gillis: You're Norma Desmond. You used to be in silent pictures. You used to be big.

Norma Desmond: I *am* big. It's the *pictures* that got small.
https://en.wikipedia.org/wiki/Planetary_nebula#Lifetime wrote: <<After a star passes through the asymptotic giant branch (AGB) phase, the short planetary nebula phase of stellar evolution begins as gases blow away from the central star at speeds of a few kilometers per second. The central star is the remnant of its AGB progenitor, an electron-degenerate carbon-oxygen core that has lost most of its hydrogen envelope due to mass loss on the AGB. As the gases expand, the central star undergoes a two-stage evolution, first growing hotter as it continues to contract and hydrogen fusion reactions occur in the shell around the core and then slowly cooling once the hydrogen shell is exhausted through fusion and mass loss. In the second phase, it radiates away its energy and fusion reactions cease, as the central star is not heavy enough to generate the core temperatures required for carbon and oxygen to fuse. During the first phase, the central star maintains constant luminosity, while at the same time it grows ever hotter, eventually reaching temperatures around 100,000 K. In the second phase, it cools so much that it does not give off enough ultraviolet radiation to ionize the increasingly distant gas cloud. The star becomes a white dwarf, and the expanding gas cloud becomes invisible to us, ending the planetary nebula phase of evolution. For a typical planetary nebula, about 10,000 years passes between its formation and recombination of the star.>>
Art Neuendorffer

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by Ann » Fri Dec 04, 2015 6:04 pm

neufer wrote:
Ann wrote:
The star that blew the Soap Bubble nebula is long dead, a stellar cinder slowly radiating its remnant heat into space.
A very hot cinder (illuminating the Soap Bubble) from a recently deceased hydrogen burning star.

The star that blew off the Soap Bubble nebula a mere few thousand years ago
currently illuminates the same as it transforms into a long lived white dwarf star.
All planetary nebulas are young, certainly.
Wikipedia wrote:
For a typical planetary nebula, about 10,000 years[12] passes between its formation and recombination of the star.
So indeed, these planetary nebulas are cosmic blinks of an eye. But as planetary nebulas go, I'm not sure that the Soap Bubble is very young, or that its central star is remarkably hot. After all, the nebula is so faint that it was discovered only seven years ago! Bear in mind that many planetary nebulas are quite bright. To be as faint as the Soap Bubble Nebula is, it seems to me that its central star must have cooled off quite a bit. Note that the Soap Bubble looks mostly red, not blue, in today's APOD, definitely less blue than the Crescent Nebula. This suggests that the Soap Bubble's dominant ionization is Ha, not the more energetic OIII.

So while the central star of the Soap Bubble shed its outer layers and illuminated them only a few millennia ago, the star is not necessarily very young as central stars of planetary nebulas go.
King Tut, older or younger than the Soap Bubble?

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by starsurfer » Fri Dec 04, 2015 6:43 pm

This is an amazing and fairly unique vista as this might possibly be the only PN and WR nebula pairing in the sky! Another contrast is that the Crescent Nebula has been known since the 18th century but the Soap Bubble Nebula was only discovered in 2008.

Visual_Astronomer

Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by Visual_Astronomer » Fri Dec 04, 2015 7:13 pm

starsurfer wrote:This is an amazing and fairly unique vista as this might possibly be the only PN and WR nebula pairing in the sky! Another contrast is that the Crescent Nebula has been known since the 18th century but the Soap Bubble Nebula was only discovered in 2008.
I was looking at the Crescent just last night, it is quite interesting with a fair amount of detail visible through narrow-band filters. The Soap Bubble, on the other hand, only appears in photographs. That's why it was only recently discovered.

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by starsurfer » Mon Dec 07, 2015 7:08 pm

Visual_Astronomer wrote:
starsurfer wrote:This is an amazing and fairly unique vista as this might possibly be the only PN and WR nebula pairing in the sky! Another contrast is that the Crescent Nebula has been known since the 18th century but the Soap Bubble Nebula was only discovered in 2008.
I was looking at the Crescent just last night, it is quite interesting with a fair amount of detail visible through narrow-band filters. The Soap Bubble, on the other hand, only appears in photographs. That's why it was only recently discovered.
Nearly all the NGC objects were discovered through visual observation. You're right that recent discoveries are only found photographically with the exception of maybe some novae or supernovae.

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by neufer » Mon Dec 07, 2015 9:19 pm

starsurfer wrote:
Nearly all the NGC objects were discovered through visual observation.
https://en.wikipedia.org/wiki/Catalogue_of_Nebulae_and_Clusters_of_Stars wrote: <<The Catalogue of Nebulae and Clusters of Stars was first published in 1786 by William Herschel in the Philosophical Transactions of the Royal Society of London. In 1789, he added another 1,000 entries, and finally another 500 in 1802, bring the total to 2,500 entries. This catalogue originated the usage of letters and catalogue numbers as identifiers. The capital "H" followed with the catalogue entry number represented the item.

In 1864, the CN was expanded into the General Catalogue of Nebulae and Clusters and Clusters of Stars (GC) by John Herschel (William's son). The GC contained 5,079 entries. Later, a complementary edition of the catalog was published posthumously as the General Catalogue of 10,300 Multiple and Double Stars. The small "h" followed with the catalogue entry number represented the item.

In 1878, John Louis Emil Dreyer published a supplement to the General Catalogue. In 1886, he suggested building a second supplement to the General Catalogue, but the Royal Astronomical Society asked Dreyer to compile a new version instead. This led to the publication of the New General Catalogue (NGC) in 1888, and its two expansions, the Index Catalogues (IC), in 1895 and 1908.>>
https://en.wikipedia.org/wiki/Astrophotography wrote: <<The first photograph of an astronomical object (the Moon) was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time. Photography revolutionized the field of professional astronomical research, with long time exposures recording hundreds of thousands of new stars and nebulae that were invisible to the human eye, leading to specialized and ever larger optical telescopes that were essentially big cameras designed to collect light to be recorded on film. Direct astrophotography had an early role in sky surveys and star classification but over time it has given way to more sophisticated equipment and techniques designed for specific fields of scientific research, with film (and later astronomical CCD cameras) becoming just one of many forms of sensor.>>
Art Neuendorffer

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by starsurfer » Tue Dec 08, 2015 7:08 pm

neufer wrote:
starsurfer wrote:
Nearly all the NGC objects were discovered through visual observation.
https://en.wikipedia.org/wiki/Catalogue_of_Nebulae_and_Clusters_of_Stars wrote: <<The Catalogue of Nebulae and Clusters of Stars was first published in 1786 by William Herschel in the Philosophical Transactions of the Royal Society of London. In 1789, he added another 1,000 entries, and finally another 500 in 1802, bring the total to 2,500 entries. This catalogue originated the usage of letters and catalogue numbers as identifiers. The capital "H" followed with the catalogue entry number represented the item.

In 1864, the CN was expanded into the General Catalogue of Nebulae and Clusters and Clusters of Stars (GC) by John Herschel (William's son). The GC contained 5,079 entries. Later, a complementary edition of the catalog was published posthumously as the General Catalogue of 10,300 Multiple and Double Stars. The small "h" followed with the catalogue entry number represented the item.

In 1878, John Louis Emil Dreyer published a supplement to the General Catalogue. In 1886, he suggested building a second supplement to the General Catalogue, but the Royal Astronomical Society asked Dreyer to compile a new version instead. This led to the publication of the New General Catalogue (NGC) in 1888, and its two expansions, the Index Catalogues (IC), in 1895 and 1908.>>
https://en.wikipedia.org/wiki/Astrophotography wrote: <<The first photograph of an astronomical object (the Moon) was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time. Photography revolutionized the field of professional astronomical research, with long time exposures recording hundreds of thousands of new stars and nebulae that were invisible to the human eye, leading to specialized and ever larger optical telescopes that were essentially big cameras designed to collect light to be recorded on film. Direct astrophotography had an early role in sky surveys and star classification but over time it has given way to more sophisticated equipment and techniques designed for specific fields of scientific research, with film (and later astronomical CCD cameras) becoming just one of many forms of sensor.>>
Thanks for the history lesson neufer! I particularly like the endeavours of Edward Emerson Barnard and his Photographic Atlas of Selected Regions of the Milky Way. Here is a small list of some Barnard dark nebulae I like:

B3 by Antonio Sánchez

B33 by Ken Crawford

B86 by NOAO

B174 by Bernhard Hubl

B203 by Bernhard Hubl

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Re: APOD: Cygnus: Bubble and Crescent (2015 Dec 04)

Post by starsurfer » Tue Dec 08, 2015 7:10 pm

starsurfer wrote:This is an amazing and fairly unique vista as this might possibly be the only PN and WR nebula pairing in the sky!
Feels weird to quote myself but there is actually another PN and WR nebula pairing, Thor's Helmet and PN G227.1+00.5, which can be seen in this image.